Index: modules/javafx.web/src/main/native/Source/JavaScriptCore/heap/BlockDirectory.cpp
--- modules/javafx.web/src/main/native/Source/JavaScriptCore/heap/BlockDirectory.cpp.orig
+++ modules/javafx.web/src/main/native/Source/JavaScriptCore/heap/BlockDirectory.cpp
@@ -66,9 +66,9 @@ void BlockDirectory::setSubspace(Subspace* subspace)
 void BlockDirectory::updatePercentageOfPagedOutPages(SimpleStats& stats)
 {
     // FIXME: We should figure out a solution for Windows and PlayStation.
-    // QNX doesn't have mincore(), though the information can be had. But since all mapped
+    // QNX and OpenBSD don't have mincore(), though the information can be had. But since all mapped
     // pages are resident, does it matter?
-#if OS(UNIX) && !PLATFORM(PLAYSTATION) && !OS(QNX) && !OS(HAIKU)
+#if OS(UNIX) && !PLATFORM(PLAYSTATION) && !OS(QNX) && !OS(HAIKU) && !OS(OPENBSD)
     size_t pageSize = WTF::pageSize();
     ASSERT(!(MarkedBlock::blockSize % pageSize));
     auto numberOfPagesInMarkedBlock = MarkedBlock::blockSize / pageSize;
